2018 Mercedes-Benz S-Class MOT pass rate, common failures & what to check
In 2025, 90.5% of Mercedes-Benz S-Class cars first used in 2018 passed their MOT first time, against 80.9% for all cars first used in 2018. Across 7,065 S-Class first tests from 2023 to 2025, the most common failure areas were tyres, suspension and noise, emissions and leaks.
This page analyses first MOT tests for Mercedes-Benz S-Class cars first used in 2018 (all trims grouped): 2021 to 2025 for the pass-rate trend, and 2023 to 2025 for the failure and advisory analysis — plus what is worth checking before you buy one.
Data: DVSA anonymised MOT tests to December 2025 · Calculated by SortedCars · Updated October 2026
How the 2018 Mercedes-Benz S-Class MOT pass rate has changed
Share of first tests passed in each year, S-Class cars first used in 2018 against all cars first used in 2018 (any make or fuel; not adjusted for mileage, fuel or use). In 2025 the S-Class figure was 9.6 points higher.
View this chart as a table
| Test year | 2018 S-Class | All cars first used 2018 | S-Class first tests |
|---|---|---|---|
| 2021 | 91.8% | 87.6% | 2,631 |
| 2022 | 92.9% | 86.3% | 2,717 |
| 2023 | 90.7% | 84.2% | 2,520 |
| 2024 | 90.3% | 82.5% | 2,361 |
| 2025 | 90.5% | 80.9% | 2,184 |
Common 2018 Mercedes-Benz S-Class MOT failures
Share of the 672 failed first tests (2023–2025) with at least one failure in each area. A test can fail in more than one area, so the shares add up to more than 100%.
Most common failure items
| DVSA failure item | Share of failed first tests | Tests |
|---|---|---|
| Tread depth: below requirements of 1.6mm | 16.7% | 112 |
| Ball joint: excessively worn | 15.6% | 105 |
| Tyre condition: has a cut in excess of the requirements deep enough to reach the ply or cords | 10.9% | 73 |
| Tyre condition: has ply or cords exposed | 9.2% | 62 |
| Malfunction indicator lamp: inoperative or indicates a malfunction | 8.0% | 54 |
Item names are DVSA’s own wording. 2023–2025 combined.
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Typical repair costs for common MOT failures
Typical UK garage prices for the job, not for an S-Class in particular, and not a quote.
| Failure item | Typical job | Typical UK price | Usual range |
|---|---|---|---|
| Ball joint: excessively worn | Ball joint replacement | £90 | £60–£150 |
From published UK repair-cost guides, checked September 2026. Only jobs with a published typical price are shown.
What to check on a 2018 Mercedes-Benz S-Class before buying
The three areas where failed first tests most often had a fault, 2023–2025.
- Tyres. Worth checking the tread depth across the whole width of each tyre, and the sidewalls for cuts, cracks and bulges.
- Suspension. Worth looking behind the front wheels with a torch at the coil springs, and listening for knocks over bumps on the test drive.
- Engine and emissions. Worth checking that the engine warning light goes out after starting, looking for oil leaks under the car, and noticing any smoke from the exhaust.
Common 2018 Mercedes-Benz S-Class MOT advisories
Advisories are points the tester noted that did not fail the car. Most common on 2018 S-Class cars, as a share of all 7,065 first tests, 2023–2025.
| DVSA advisory item | Share of first tests | Tests |
|---|---|---|
| Tread depth: worn close to legal limit/worn on edge | 11.5% | 809 |
| Brake pads: wearing thin | 4.7% | 332 |
| Ball joint: has slight play | 3.5% | 250 |
| Brake discs: worn, pitted or scored, but not seriously weakened | 3.3% | 231 |
| Brake discs: worn, but not excessively | 2.6% | 183 |
Questions about the 2018 Mercedes-Benz S-Class MOT
What is the MOT pass rate of a 2018 Mercedes-Benz S-Class?
In 2025, 90.5% of S-Class cars first used in 2018 passed their MOT first time, against 80.9% for all cars first used in 2018. A car fixed during the test counts as a fail.
What does a 2018 S-Class most often fail its MOT on?
Tyres (in 46.0% of failed first tests, 2023–2025), suspension (17.7%) and noise, emissions and leaks (12.9%). The single most common item was “Tread depth: below requirements of 1.6mm” (16.7%).
How often does a 2018 Mercedes-Benz S-Class fail its MOT?
In 2025, 9.5% of first tests on S-Class cars first used in 2018 did not pass first time: 7.9% failed, and a further 1.6% had a fault fixed during the test (counted as a fail here). Across 2023–2025, 672 of 7,065 first tests did not pass first time.
What are the most common 2018 Mercedes-Benz S-Class MOT advisories?
“Tread depth: worn close to legal limit/worn on edge” (on 11.5% of first tests, 2023–2025), “Brake pads: wearing thin” (4.7%), “Ball joint: has slight play” (3.5%), “Brake discs: worn, pitted or scored, but not seriously weakened” (3.3%) and “Brake discs: worn, but not excessively” (2.6%).
Is a 2018 Mercedes-Benz S-Class reliable?
An MOT pass rate shows what failed at the test, not how reliable a car is. For this group of cars the first-time pass rate went from 91.8% in 2021 to 90.5% in 2025. For one particular car, its own MOT history matters more than the average.
Other cars first used in 2018
The most-tested cars from the same year. Each page uses the same method.
2018 Ford Fiesta MOT statistics · 2018 Volkswagen Golf MOT statistics · 2018 Vauxhall Corsa MOT statistics · 2018 Ford Focus MOT statistics · 2018 Nissan Qashqai MOT statistics
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